Method and apparatus for configuring frame structure for new radio access technology in wireless communication system

ABSTRACT

For supporting a new radio access technology (new RAT, or NR), a frame structure for the new RAT may be configured. A network node configures a frame in which a first cyclic prefix (CP) is allocated to a first symbol in every 0.5 ms and a second CP is allocated to remaining symbols in every 0.5 ms. In this case, a length of the first CP is longer than a length of the second CP.

TECHNICAL FIELD

The present invention relates to wireless communications, and moreparticularly, to a method and apparatus for configuring a framestructure for a new radio access technology (RAT) in a wirelesscommunication system.

BACKGROUND ART

3rd generation partnership project (3GPP) long-term evolution (LTE) is atechnology for enabling high-speed packet communications. Many schemeshave been proposed for the LTE objective including those that aim toreduce user and provider costs, improve service quality, and expand andimprove coverage and system capacity. The 3GPP LTE requires reduced costper bit, increased service availability, flexible use of a frequencyband, a simple structure, an open interface, and adequate powerconsumption of a terminal as an upper-level requirement.

As more and more communication devices require more communicationcapacity, there is a need for improved mobile broadband communicationover existing radio access technology. Also, massive machine typecommunications (MTC), which provides various services by connecting manydevices and objects, is one of the major issues to be considered in thenext generation communication. In addition, communication system designconsidering reliability/latency sensitive service/UE is being discussed.The introduction of next generation radio access technology consideringenhanced mobile broadband communication, massive MTC, ultra-reliable andlow latency communication (URLLC) is discussed. This new technology maybe called new radio access technology (RAT) for convenience.

In the new RAT, analog beamforming may be introduced. In case ofmillimeter wave (mmW), the wavelength is shortened so that a pluralityof antennas can be installed in the same area. For example, in the 30GHz band, a total of 100 antenna elements can be installed in a2-dimension array of 0.5 lambda (wavelength) intervals on a panel of 5by 5 cm with a wavelength of 1 cm. Therefore, in mmW, multiple antennaelements can be used to increase the beamforming gain to increase thecoverage or increase the throughput.

In this case, if a transceiver unit (TXRU) is provided so thattransmission power and phase can be adjusted for each antenna element,independent beamforming is possible for each frequency resource.However, installing a TXRU on all 100 antenna elements has a problem interms of cost effectiveness. Therefore, a method of mapping a pluralityof antenna elements to one TXRU and adjusting the direction of a beamusing an analog phase shifter is considered. This analog beamformingmethod has a disadvantage that it cannot perform frequency selectivebeaming because it can make only one beam direction in all bands.

A hybrid beamforming with B TXRUs, which is an intermediate form ofdigital beamforming and analog beamforming, and fewer than Q antennaelements, can be considered. In this case, although there is adifference depending on the connection method of the B TXRU and Qantenna elements, the direction of the beam that can be simultaneouslytransmitted is limited to B or less.

For operating new RAT efficiently, various schemes have been discussed.Specifically, a new frame structure may need to be required.

DISCLOSURE OF INVENTION Technical Problem

The present provides a method and apparatus for configuring a framestructure for a new radio access technology (RAT) in a wirelesscommunication system. The present invention provides a method andapparatus for handling scalable numerology cyclic prefix (CP). Thepresent invention further provides a method and apparatus formultiplexing different numerologies in a carrier. The present inventionproposes frame structure, particularly focusing on cyclic prefix (CP)which will allow the same slot length except for the first slot in every0.5 ms and also allow multiplexing of normal CP and extended CP ofdifferent numerologies in every mini-slot (e.g. 1 or 2 symbols ofsmaller subcarrier spacing).

Solution to Problem

In an aspect, a method for configuring a frame by a network node in awireless communication system is provided. The method includesconfiguring a frame in which a first cyclic prefix (CP) is allocated toa first symbol in every 0.5 ms and a second CP is allocated to remainingsymbols in every 0.5 ms, and communicating with a user equipment (UE) byusing the frame. A length of the first CP is longer than a length of thesecond CP.

In another aspect, a network node in a wireless communication system isprovided. The network node includes a memory, a transceiver, aprocessor, coupled to the memory and the transceiver, that configures aframe in which a first cyclic prefix (CP) is allocated to a first symbolin every 0.5 ms and a second CP is allocated to remaining symbols inevery 0.5 ms, and controls the transceiver to communicate with a userequipment (UE) by using the frame. A length of the first CP is longerthan a length of the second CP.

Advantageous Effects of Invention

New frame structure can be configured for new RAT.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a wireless communication system.

FIG. 2 shows structure of a radio frame of 3GPP LTE.

FIG. 3 shows a resource grid for one downlink slot.

FIG. 4 shows an example of subframe type for new RAT.

FIG. 5 shows an example of a frame structure for a new RAT.

FIG. 5 shows an example of a frame structure for a new RAT.

FIG. 6 shows an example of CP lengths according to an embodiment of thepresent invention.

FIG. 7 shows another example of CP lengths according to an embodiment ofthe present invention.

FIG. 8 shows an example of multiplexing different numerologies in asingle carrier according to an embodiment of the present invention.

FIG. 9 shows another example of multiplexing different numerologies in asingle carrier according to an embodiment of the present invention.

FIG. 10 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention.

FIG. 11 shows an example of a frame structure considering multiplexingof different subcarrier spacing according to an embodiment of thepresent invention.

FIG. 12 shows another example of a frame structure consideringmultiplexing of different subcarrier spacing according to an embodimentof the present invention.

FIG. 13 shows another example of a frame structure consideringmultiplexing of different subcarrier spacing according to an embodimentof the present invention.

FIG. 14 shows another example of a frame structure consideringmultiplexing of different subcarrier spacing according to an embodimentof the present invention.

FIG. 15 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention.

FIG. 16 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention.

FIG. 17 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention.

FIG. 18 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention.

FIG. 19 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention.

FIG. 20 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention.

FIG. 21 shows an example of subframe indexing for different numerologiesaccording to an embodiment of the present invention.

FIG. 22 shows another example of subframe indexing for differentnumerologies according to an embodiment of the present invention.

FIG. 23 shows a method for configuring a frame by a network nodeaccording to an embodiment of the present invention.

FIG. 24 shows a wireless communication system to implement an embodimentof the present invention.

MODE FOR THE INVENTION

Techniques, apparatus and systems described herein may be used invarious wireless access technologies such as code division multipleaccess (CDMA), frequency division multiple access (FDMA), time divisionmultiple access (TDMA), orthogonal frequency division multiple access(OFDMA), single carrier frequency division multiple access (SC-FDMA),etc. The CDMA may be implemented with a radio technology such asuniversal terrestrial radio access (UTRA) or CDMA2000. The TDMA may beimplemented with a radio technology such as global system for mobilecommunications (GSM)/general packet radio service (GPRS)/enhanced datarates for GSM evolution (EDGE). The OFDMA may be implemented with aradio technology such as institute of electrical and electronicsengineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20,evolved-UTRA (E-UTRA) etc. The UTRA is a part of a universal mobiletelecommunication system (UMTS). 3rd generation partnership project(3GPP) long term evolution (LTE) is a part of an evolved-UMTS (E-UMTS)using the E-UTRA. The 3GPP LTE employs the OFDMA in downlink (DL) andemploys the SC-FDMA in uplink (UL). LTE-advance (LTE-A) is an evolutionof the 3GPP LTE. For clarity, this application focuses on the 3GPPLTE/LTE-A. However, technical features of the present invention are notlimited thereto.

FIG. 1 shows a wireless communication system. The wireless communicationsystem 10 includes at least one evolved NodeB (eNB) 11. Respective eNBs11 provide a communication service to particular geographical areas 15a, 15 b, and 15 c (which are generally called cells). Each cell may bedivided into a plurality of areas (which are called sectors). A userequipment (UE) 12 may be fixed or mobile and may be referred to by othernames such as mobile station (MS), mobile terminal (MT), user terminal(UT), subscriber station (SS), wireless device, personal digitalassistant (PDA), wireless modem, handheld device. The eNB 11 generallyrefers to a fixed station that communicates with the UE 12 and may becalled by other names such as base station (BS), base transceiver system(BTS), access point (AP), etc.

In general, a UE belongs to one cell, and the cell to which a UE belongsis called a serving cell. An eNB providing a communication service tothe serving cell is called a serving eNB. The wireless communicationsystem is a cellular system, so a different cell adjacent to the servingcell exists. The different cell adjacent to the serving cell is called aneighbor cell. An eNB providing a communication service to the neighborcell is called a neighbor eNB. The serving cell and the neighbor cellare relatively determined based on a UE.

This technique can be used for DL or UL. In general, DL refers tocommunication from the eNB 11 to the UE 12, and UL refers tocommunication from the UE 12 to the eNB 11. In DL, a transmitter may bepart of the eNB 11 and a receiver may be part of the UE 12. In UL, atransmitter may be part of the UE 12 and a receiver may be part of theeNB 11.

The wireless communication system may be any one of a multiple-inputmultiple-output (MIMO) system, a multiple-input single-output (MISO)system, a single-input single-output (SISO) system, and a single-inputmultiple-output (SIMO) system. The MIMO system uses a plurality oftransmission antennas and a plurality of reception antennas. The MISOsystem uses a plurality of transmission antennas and a single receptionantenna. The SISO system uses a single transmission antenna and a singlereception antenna. The SIMO system uses a single transmission antennaand a plurality of reception antennas. Hereinafter, a transmissionantenna refers to a physical or logical antenna used for transmitting asignal or a stream, and a reception antenna refers to a physical orlogical antenna used for receiving a signal or a stream.

FIG. 2 shows structure of a radio frame of 3GPP LTE. Referring to FIG.2, a radio frame includes 10 subframes. A subframe includes two slots intime domain. A time for transmitting one transport block by higher layerto physical layer (generally over one subframe) is defined as atransmission time interval (TTI). For example, one subframe may have alength of 1 ms, and one slot may have a length of 0.5 ms. One slotincludes a plurality of orthogonal frequency division multiplexing(OFDM) symbols in time domain. Since the 3GPP LTE uses the OFDMA in theDL, the OFDM symbol is for representing one symbol period. The OFDMsymbols may be called by other names depending on a multiple-accessscheme. For example, when SC-FDMA is in use as a UL multi-access scheme,the OFDM symbols may be called SC-FDMA symbols. A resource block (RB) isa resource allocation unit, and includes a plurality of contiguoussubcarriers in one slot. The structure of the radio frame is shown forexemplary purposes only. Thus, the number of subframes included in theradio frame or the number of slots included in the subframe or thenumber of OFDM symbols included in the slot may be modified in variousmanners.

The wireless communication system may be divided into a frequencydivision duplex (FDD) scheme and a time division duplex (TDD) scheme.According to the FDD scheme, UL transmission and DL transmission aremade at different frequency bands. According to the TDD scheme, ULtransmission and DL transmission are made during different periods oftime at the same frequency band. A channel response of the TDD scheme issubstantially reciprocal. This means that a DL channel response and a ULchannel response are almost the same in a given frequency band. Thus,the TDD-based wireless communication system is advantageous in that theDL channel response can be obtained from the UL channel response. In theTDD scheme, the entire frequency band is time-divided for UL and DLtransmissions, so a DL transmission by the eNB and a UL transmission bythe UE cannot be simultaneously performed. In a TDD system in which a ULtransmission and a DL transmission are discriminated in units ofsubframes, the UL transmission and the DL transmission are performed indifferent subframes. In a TDD system, to allow fast switching between DLand UL, UL and DL transmission may be performed within a samesubframe/slot in time division multiplexing (TDM)/frequency divisionmultiplexing (FDM) manner.

FIG. 3 shows a resource grid for one downlink slot. Referring to FIG. 3,a DL slot includes a plurality of OFDM symbols in time domain. It isdescribed herein that one DL slot includes 7 OFDM symbols, and one RBincludes 12 subcarriers in frequency domain as an example. However, thepresent invention is not limited thereto. Each element on the resourcegrid is referred to as a resource element (RE). One RB includes 12×7 or12×14 resource elements. The number NDL of RBs included in the DL slotdepends on a DL transmit bandwidth. The structure of a UL slot may besame as that of the DL slot. The number of OFDM symbols and the numberof subcarriers may vary depending on the length of a CP, frequencyspacing, etc. For example, in case of a normal cyclic prefix (CP), thenumber of OFDM symbols is 7 or 14, and in case of an extended CP, thenumber of OFDM symbols is 6 or 12. One of 128, 256, 512, 1024, 1536,2048, 4096 and 8192 may be selectively used as the number of subcarriersin one OFDM symbol.

5th generation mobile networks or 5th generation wireless systems,abbreviated 5G, are the proposed next telecommunications standardsbeyond the current 4G LTE/international mobile telecommunications(IMT)-dvanced standards. 5G includes both new radio access technology(new RAT or NR) and LTE evolution. Hereinafter, among 5G, new RAT willbe focused. 5G planning aims at higher capacity than current 4G LTE,allowing a higher density of mobile broadband users, and supportingdevice-to-device, ultra-reliable, and massive machine communications. 5Gresearch and development also aims at lower latency than 4G equipmentand lower battery consumption, for better implementation of the Internetof things.

It is expected that different frame structure may be necessary for thenew RAT. Particularly, different frame structure in which UL and DL maybe present in every subframe or may change very frequently in the samecarrier may be necessary for the new RAT. Different application mayrequire different minimum size of DL or UL portions to support differentlatency and coverage requirements. For example, massive machine-typecommunication (mMTC) for high coverage case may require relatively longDL and UL portion so that one transmission can be successfullytransmitted. Furthermore, due to different requirement onsynchronization and tracking accuracy requirements, different subcarrierspacing and/or different CP length may be considered. In this sense, itis necessary to consider mechanisms to allow different frame structurescoexisting in the same carrier and be operated by the same cell/eNB.

In the new RAT, utilizing a subframe in which downlink and uplink arecontained may be considered. This scheme may be applied for pairedspectrum and unpaired spectrum. The paired spectrum means that onecarrier consists of two carriers. For example, in the paired spectrum,the one carrier may include a DL carrier and an UL carrier, which arepaired with each other. In the paired spectrum, communication, such asDL, UL, device-to-device communication, and/or relay communication, maybe performed by utilizing the paired spectrum. The unpaired spectrummeans that that one carrier consists of only one carrier, like thecurrent 4G LTE. In the unpaired spectrum, communication, such as DL, UL,device-to-device communication, and/or relay communication, may beperformed in the unpaired spectrum.

Further, in the new RAT, the following subframe types may be consideredto support the paired spectrum and the unpaired spectrum mentionedabove.

(1) Subframes Including DL Control and DL Data

(2) Subframes including DL control, DL data, and UL control

(3) Subframes including DL control and UL data

(4) Subframes including DL control, UL data, and UL control

(5) Subframes including access signals or random access signals or otherpurposes.

(6) Subframes including both DL/UL and all UL signals.

However, the subframe types listed above are only exemplary, and othersubframe types may also be considered.

FIG. 4 shows an example of subframe type for new RAT. The subframe shownin FIG. 4 may be used in TDD system of new RAT, in order to minimizelatency of data transmission. Referring to FIG. 4, the subframe contains14 symbols in one TTI, like the current subframe. However, the subframeincludes DL control channel in the first symbol, and UL control channelin the last symbol. The remaining symbols may be used for DL datatransmission or for UL data transmission. According to this subframestructure, DL transmission and UL transmission may sequentially proceedin one subframe. Accordingly, DL data may be transmitted in thesubframe, and UL acknowledgement/non-acknowledgement (ACK/NACK) may alsobe received in the subframe. In this manner, the subframe shown in FIG.4 may be referred to as self-contained subframe. As a result, it maytake less time to retransmit data when a data transmission error occurs,thereby minimizing the latency of final data transmission. In theself-contained subframe structure, a time gap may be required for thetransition process from the transmission mode to the reception mode orfrom the reception mode to the transmission mode. For this purpose, someOFDM symbols at the time of switching from DL to UL in the subframestructure may be set to the guard period (GP).

Further, in the new RAT, it may be considered to have differentdurations of TTI for different services with or without differentsubcarrier spacing. For example, a frame structure type 1 (FS1) may beformed to support, e.g. enhanced mobile broadband (eMBB) use cases whilea frame structure type 2 (FS2) may be formed to support, e.g. mMTC. Foranother example, single cell transmission and SFN transmission mayutilize different subcarrier spacing. In the description below, for theconvenience, it is assumed that the FS1 and FS2 are configured andcoexist in the same carrier. The FS1 may be a baseline frame structureused for such as for eMBB use cases or typical use cases. The FS2 may beused for some other applications such as mMTC, ultra-reliable and lowlatency communication (URLLC), an enhanced vehicle-to-everything (eV2X)communication. The network or a cell may support one or multiple framestructures at the same time. For the convenience, the present inventionmay discuss relationship between two frame structures. However, morethan two frame structures may be supported simultaneously. Further, eNBin the description below may be replaced by gNB which is entity of thenew RAT. The eNB may refer any network entity relevant in eachcommunication protocol framework without the loss of generality.

FIG. 5 shows an example of a frame structure for a new RAT. Referring toFIG. 5, frame structures utilizing different subcarrier spacing inpotentially different subbands are described. It is shown that FS1 isthe same as the conventional frame structure, as one TTI includes 14symbols. That is, one TTI of FS1 is 1 ms. On the other hand, one TTI ofFS2 is ‘m’ ms. ‘m’ may be predetermined. Or, ‘m’ may be determined basedon subcarrier spacing used for mMTC.

1. Scalable Numerology CP Handling

To support various usage scenarios and different deployment scenarioswith different CP length and latency requirements, multiple subcarrierspacing may be considered. Frame structures with multiple subcarrierspacing may be nested with each other. However, if different CP lengthis used in any frame structure, it may need to be clarified how thedifferent CP is inherited to another frame structure. For example, ifFS1 with subcarrier spacing 1 (hereinafter SC1) and FS2 with subcarrierspacing 2 (hereinafter, SC2) are to be nested with each other and SC2 is2 times of SC1, it may be desirable to scale down the CP lengthproportionally. In this case, if there is any special symbol(s) withdifferent CP compared to other symbols, some handing may be necessary.

For example, it may be assumed that there are OFDM symbols (OS) from OS1. . . OSk in a slot (e.g. k=7) and OS1 . . . OS2k in a subframe.Further, it may be assumed that OS1 has longer CP than other OSs in SC1.In this case, handling CP of SC2 to be aligned with SC1 may follow atleast one options described below.

(1) At OS level: CP of OS1 and OS2 in SC2 may be scaled down from CP ofOS1 in SC1. That is, CP of two OSs in SC2 corresponding to the first OSin SC1 may be reduced to half from CP of SC1. CP of other OSs in SC2 maybe scaled down or determined by OSm's CP=OSi's CP/2, where m=2*i. Thisapproach may be assumed throughout the description below.

(2) At slot boundary level (e.g. OS1 . . . OSk): Two numerologies may bealigned at the slot/subframe boundary of SC1. In this case, extra CPlength may be applied towards any OS in SC2 (i.e. OS1 . . . OSk) whichis overlapped with special OS in SC1. For example, first one OS in SC2may carry the extra CP length. Alternatively, first two OS in SC2 maycarry the extra CP length.

(3) At slot/subframe boundary level of SC2: SC2 may be aligned with timeduration of slot/subframe of SC1/m, when SC2=SC1*m (m>1). Oneslot/subframe duration of SC1 may be equally divided into m, and theslot/subframe duration of SC2 may always be aligned with the equallydivided duration of SC1. This option may be a special case of option (2)described above.

(4) At multi-slot/Subframe boundary level: Two numerologies may bealigned at multiple subframe levels. For example, m slots of SC2 may beplaced over n slots of SC1. This option may be similar to “non-alignedcase”. However, by utilizing this option, with different CP, at leastalignments at ‘n’ slots of SC1 may be feasible. For example, 1 slot of3.75 kHz subcarrier spacing may be aligned with 4 slots of 15 kHzsubcarrier spacing, with some margin in 3.75 kHz subcarrier spacing.

There may be more than two numerologies at the system. In this case, areference subcarrier spacing may be defined. The reference subcarrierspacing may be fixed to e.g. 15 kHz, or LTE numerology. Or, thereference subcarrier spacing may be configured by higher layer (e.g. 30kHz). Or, the reference subcarrier spacing may be determined via cellsearch implicitly. For the reference subcarrier spacing, it may beassumed that it consist of 7 OS in a slot or subframe, and one OS mayhave special CP length compared to other OSs. For example, 15 kHzsubcarrier spacing may be a reference subcarrier spacing in below 6 GHz,and 60 kHz subcarrier spacing may be a reference subcarrier spacing inabove 6 GHz. Multiple special OS may also be present and mechanismsdescribed in the present invention may be recursively applied. In thiscase, subframe may need to be elaborated such that nested framestructure starts from a reference subcarrier spacing. In other words,within symbol-level alignment, one special OS of reference subcarrierspacing may be configured, and CP of other OSs in reference subcarrierspacing may be constructed such that m*CP1 may be distributed over m OSscorresponding to special OS in SC0. CP1 is CP of the special OS, and mis SCm=m*SC0, and SC0 is the reference subcarrier spacing. If m is lessthan 1, any corresponding OS to special OS in SC0 may have specialtreatment. On the other hand, within slot boundary level alignment, CPformation may be aligned with each other as similar as possible (i.e.CPx, CP2 . . . CP2 (7 OS), where CP2 is the CP length of normal OS inSC0, and where CPx is CP1 if subframe or slot index i of SCm is suchthat i/m=0 (if m>1), and i %1/m=0 (if m<1), and CPx is CP2 otherwise).

In the description below, subframe or slot may indicate a duration of 7OS. With multiple subframe/slot boundary level alignment, CPx may bedistributed rather evenly or depending on various patterns. For example,CPx may be CP1 of every first OS in every subframe of SCm (if m>1).

In 3GPP LTE, with fast Fourier transform (FFT) size of 2048 with 15 kHzsubcarrier spacing, Ts is defined as 1/(15000*2048). Table 1 belowdifferent representation of Ts based on Ts of 3GPP LTE, according to FFTsize and subcarrier spacing. Even though not described in Table 1, forother subcarrier spacing, e.g. 120 or 240 kHz subcarrier spacing, or forother FFT size, Table 1 may be simply expanded.

TABLE 1 Subcarrier FFT size spacing In Ts Value Ts-1 2048 15 kHz Ts1/(15000 *2048) Ts-2 4096 15 kHz Ts/2 1/(15000 *4096) Ts-3 2048 30 kHzTs/2 1/(30000 *2048) Ts-4 4096 30 kHz Ts/4 1/(30000 *4096) Ts-5 1024 30kHz Ts 1/(30000 *1024) Ts-6 2048 60 kHz Ts/4 1/(60000 *2048) Ts-7 409660 kHz Ts/8 1/(60000 *4096) Ts-8 1024 60 kHz Ts/2 1/(60000 *1024) Ts-9512 60 kHz Ts 1/(60000 *512) Ts-10 2048 7.5 kHz  2 *Ts 1/(7500 *2048)Ts-11 4096 7.5 kHz Ts 1/(7500 *4096) Ts-12 1024 7.5 kHz  4 * Ts 1/(7500*1024) Ts-13 2048 3.75 kHz  4* Ts 1/(3750*2048) Ts-14 128 3.75 kHz  64 *Ts 1/(3750 * 128) Ts-15 64 3.75 kHz 128 * Ts 1/(3750 * 64) Ts-16 32 3.75kHz 256 * Ts 1/(3750 * 32) Ts-17 16 3.75 kHz 512 * Ts 1/(3750 * 512)Ts-18 128 15 kHz  16 * Ts 1/(15000 *128) Ts-19 64 15 kHz  32 * Ts1/(15000 * 64) Ts-20 32 15 kHz  64 * Ts 1/(15000 *32) Ts-21 128 30 kHz 16 * Ts 1/(30000 *128) Ts-22 64 30 kHz  32 * Ts 1/(30000 * 64) Ts-23 3230 kHz  64 * Ts 1/(30000 *32) Ts-24 128 60 kHz  16 * Ts 1/(60000 *128)Ts-25 64 60 kHz  32 * Ts 1/(60000 * 64) Ts-26 32 60 kHz  64 * Ts1/(60000 *32)

If 15 kHz subcarrier spacing is a reference subcarrier spacing and thenetwork uses 15, 30, 60 kHz subcarrier spacing in below 6 GHz, one ofoptions listed in Table 1 may be addressed. If 60 kHz subcarrier spacingis a reference subcarrier spacing and the network uses 60, 120, 240 kHzsubcarrier spacing in above 6 GHz may correspond to 15, 30, 60 kHz inTable 1.

Basic options of CP lengths for reference subcarrier spacing in a slotwill be described, which are identified without consideration of nestedframe structure between different subcarrier spacing. Some values may becompatible to support nested frame structure. Different options may beused at the same time depending on mechanism to handle the alignmentbetween different numerologies. The basic rules of creating CP optionsmay be summarized as follows.

(1) Alt 1: The subframe duration is assumed as “D”, which may be DLsubframe duration of 3GPP LTE. 7 OS including CP may fulfill “D” withoutany left-over. CPs may be equally divided which gives base CP length(smaller value), and if left-over is present, the left-over may be addedto one or a few OS.

(2) Alt 2: Similar to the Alt 1 described above, but CPs may be equallydivided with reserved left-over.

(3) Alt 3: To align different subcarrier spacing and/or numerology atsymbol level as much as possible with the reference subcarrier spacingor numerology, necessary CP handling may be achieved. For example, itmay be assumed that CPx is the CP length of OSx in SC0 (i.e. referencesubcarrier spacing). For CPy of OSy(s) in SC1 overlapped with OSx, CPymay be CPx/m, where SC1=m*SC0 (m>1). For CPy of OSy in SC2 overlappedwith OSx(s), CPy may be sum (CPx) of overlapped CPx (m<1)

If CPy is not integer value, at least one of the following options maybe used.

1) In order to avoid left-over, all CPy may be gathered, and Alt 1described above may be applied. That is, between this option and Alt 1,only the CP determination mechanism may be different

2) Floor value may be taken, Alt 2 described above may be applied. Thatis, between this option and Alt 2, only the CP determination mechanismmay be different.

3) CPs of two or multiple OSs may be added and divided into two ormultiple integer values. For example, for 4.5, 4.5 for OS1 and OS2,summation value 9 may be divided into 5 and 4 for OS1 and OS2,respectively.

If FFT size are different from each other in SC0 and SC1, for CPy ofOSy(s) in SC1 overlapped with OSx, CPy may be CPx/m/n, where SC1=m*SC0(m>1) and FFT (SC1)=FFT (SC0)/n. For CPy of OSy in SC2 overlapped withOSx(s), CPy may be sum (CPx)/n of overlapped CPx (m<1), where FFT(SC2)=FFT (SC0)/n.

If CPy is not integer value, at least one of the following options maybe used.

1) In order to avoid left-over, all CPy may be gathered, and Alt 1described above may be applied. That is, between this option and Alt 1,only the CP determination mechanism may be different

2) Floor value may be taken, Alt 2 described above may be applied. Thatis, between this option and Alt 2, only the CP determination mechanismmay be different.

3) CPs of two or multiple OSs may be added and divided into two ormultiple integer values. For example, for 4.5, 4.5 for OS1 and OS2,summation value 9 may be divided into 5 and 4 for OS1 and OS2,respectively.

For example, for 15 kHz subcarrier spacing and 128 FFT size, CP lengthmay be {10, 9, 9, 9, 9, 9, 9} in a slot.

For example, for 30 kHz subcarrier spacing and 128 FFT size, CP lengthmay be {10, 10, 9, 9, 9, 9, 9} {9, 9, 9, 9, 9, 9, 9} in even slot/oddslot.

For example, for 30 kHz subcarrier spacing and 64 FFT size, CP lengthmay be {5, 5, 4, 5, 4, 5, 4} {5, 4, 5, 4, 5, 4, 5}.

For example, 30 kHz subcarrier spacing and 32 FFT size, CP length may be{3, 2, 2, 2, 3, 2, 2} {2, 3, 2, 2, 2, 3, 2} or {3, 2, 2, 3, 2, 2, 2} {3,2, 2, 2, 3, 2, 2}.

For example, for 60 kHz subcarrier spacing and 128 FFT size, CP lengthmay be {10, 10, 10, 10, 9, 9, 9} {9, 9, 9, 9, 9, 9, 9} {9, 9, 9, 9, 9,9, 9} {9, 9, 9, 9, 9, 9, 9} from 1st slot to 4th slot (repeated in 28OS).

For example, for 60 kHz subcarrier spacing and 64 FFT size, CP lengthmay be {5, 5, 5, 5, 5, 4, 5} {4, 5, 4, 5, 4, 5, 4} {5, 4, 5, 4, 5, 4, 5}{4, 5, 4, 5, 4, 5, 4} or {5, 5, 5, 5, 4, 5, 4} {5, 4, 5, 4, 5, 4, 5} {4,5, 4, 5, 4, 5, 4} {5, 4, 5, 4, 5, 4, 5} from 1st slot to 4th slot(repeated in 28 OS).

For example, for 60 kHz subcarrier spacing and 32 FFT size, CP lengthmay be {3, 2, 3, 2, 3, 2, 2} {2, 3, 2, 2, 2, 3, 2} {2, 2, 3, 2, 2, 2, 3}{2, 2, 2, 3, 2, 2, 2} or {3, 2, 3, 2, 2, 3, 2} {2, 2, 3, 2, 2, 2, 3} {2,2, 2, 3, 2, 2, 2} {3, 2, 2, 2, 3, 2, 2} from 1st slot to 4th slot(repeated in 28 OS).

Table 2 shows basic options of CP length.

TABLE 2 FFT Subcarrier size Spacing In Ts CP length in normal CP in Ts-xTs-1 2048 15 kHz Ts Alt 1: {160, 144, 144, 144, 144, 144, 144}Alt 2:{144, 144, 144, 144, 144, 144, 144}Alt 3: {160, 160, 144, 144, 144, 144,144, 144 . . . 144} (14 OS) if SC0 = 7.5 kHz Ts-2 4096 15 kHz Ts/2 Alt1: {320, 288, 288, 288, 288, 288, 288}Alt 2: {288, 288, 288, 288, 288,288, 288}Alt 3: {320, 320, 288, 288, 288, 288, 288, 288 . . . 288}(14OS) if SC0 = 7.5 kHz Ts-3 2048 30 kHz Ts/2 Alt 1: {160, 144, 144,144, 144, 144, 144} Alt 2: {144, 144, 144, 144, 144, 144, 144}Alt 3:{160, 160, 144, 144, 144, 144, 144, 144 . . .} (14OS) if SC0 = 15kHz(any combination where 160 can be placed in different position isalso considered) Ts-4 4096 30 kHz Ts/4 Alt 1: {320, 288, 288, 288, 288,288, 288}Alt 2: {all 288}Alt 3: {two 320, 12 times of 288} (14 OS) (anycombination where 320 is placed in different position(s) is alsoconsidered) Ts-5 1024 30 kHz Ts Alt 1: {80, 72, 72, 72, 72, 72, 72,72}Alt 2: {72, 72, 72, 72, 72, 72, 72, 72}Alt 3: {80, 80, 72, 72 . . .72, 72, 72} (any combination where 80 is placed in different position(s)is also considered) Ts-6 2048 60 kHz Ts/4 Alt 1: {one 160, six 144 over7 OS} or {one 208, 27 times of 144 over 28 OS}, {two 176, 26 times of144 over 28 OS}, {four 160, 24 times of 144 over 28 OS}Alt 2: {seven 144over 7 OS}Alt 3: {four 160, 24 times of 144 over 28 OS} or {two 176, 26times of 144 over 28 OS} or {one 208, 27 times of 144 over 28 OS} if SC0= 15 kHz(any combination where 160, 176, 208 is placed in differentposition(s) is also considered) Ts-7 4096 60 kHz Ts/8 Alt 1: {one 320,six 288 over 7 OS} or {one 416, 27 times of 288 over 28 OS}, {two 352,26 times of 288 over 28 OS}, {four 320, 24 times of 288 over 28 OS}Alt2: {seven 288 over 7 OS}Alt 3: {four 320, 24 times of 288 over 28 OS} or{two 352, 26 times of 144 over 28 OS} or {one 416, 27 times of 288 over28 OS} if SC0 = 15 kHz(any combination where 320, 352, 416 is placed indifferent position(s) is also considered) {one 320, six 288 over 7 OS},{seven 288 over 7 OS} or {two 320, five 288 over 7 OS} or {four 320,three 288 over 7 OS} Ts-8 1024 60 kHz Ts/2 (similar to Ts-6 by replacing160 with 80, 144 with 72, 208 with 104, 176 with 88) Ts-9 512 60 kHz Ts(similar to Ts-6 by replacing 160 with 40, 144 with 36, 208 with 52, 176with 44) Ts-10 2048 7.5 kHz  2 *Ts Alt 1: {160, 144, 144, 144, 144, 144,144}Alt 2: {144 . . . 144} or {80, 72 . . . 72} {72 . . . 72} (7 OS)Alt3: {152, 144, 144, 152, 144, 144, 144}(any combination where 160, 176,208 is placed in different position(s) is also considered) Ts-11 40967.5 kHz Ts (similar to Ts-10 by multiplying each value by 2, i.e. 160with 320) Ts-12 1024 7.5 kHz  4 * Ts (similar to Ts-10 by multiplyingeach value by ½, i.e. 160 with 80) Ts-13 2048 3.75 kHz  4* Ts Alt 1:{160, 144, 144, 144, 144, 144, 144}Alt 2: {144 . . . 144}, or {80, 72,72, 72, 72, 72, 72, 72} or {40, 36 . . . 36} or {72 . . . 72} or {36 . .. 36} or {144 . . . 144}Alt 3: {592, 592, 576, 592, 576, 592, 576}(anycombination set of numbers in a set is possible) Ts-14 128 3.75 kHz 64 * Ts Alt 1: {10, 9, 9, 9 9, 9, 9}Alt 2: {9 . . . 9} (remaining 1Ts-14) or {5, 5, 5, 5, 4, 4, 4} (remaining 32 Ts-14) or {4 . . . 4}(remaining 36 Ts-14)Alt 3: N/A(any combination set of numbers in a setis possible) Ts-15 64 3.75 kHz 128 * Ts (7 OS)Alt 1: {5, 5, 5, 5, 4, 4,4} or {5, 5, 4, 5, 4, 5, 4} or {5, 4, 5, 4, 5, 4, 5} or {4 times of 5and 3 times of 4}Alt 2: {4, 4, 4, 4, 4, 4, 4} (remaining 4 Ts-15) Or {3,3, 2, 2, 2, 2, 2} (remaining of 16 Ts- 15) or {2 . . . 2} (remaining of18 Ts-15)Alt 3: N/ A(any combination set of numbers in a set ispossible) Ts-16 32 3.75 kHz 256 * Ts (7 OS)Alt 1: {3, 3, 2, 2, 2, 2, 2}or {3, 2, 2, 3, 2, 2, 2} or {3 2 2 2 2 2 3} or (any combination of 2times of 3 and 4 times of 2)Alt 2: {2 . . . 2} (remaining of 2 Ts-16) or{2, 1 . . . 1} (remaining of 8 Ts-16) or {1, 1 . . . 1} (remaining of 8Ts-16) Ts-17 16 3.75 kHz 512 * Ts (7 OS)Alt 1: {2, 1, 1, 1, 1, 1, 1} or(any combination of 1 times of 2 and 6 times of l)Alt 2: {1, 1 . . .}(remaining of 1 Ts-17) Ts-18 128 15 kHz  16 * Ts (7 OS) Alt 1: {10, 9,9, 9, 9, 9, 9}Alt 2: {9 . . . 9} (remaining 1 Ts-14) or {5, 5, 5, 5, 4,4, 4} (remaining 32 Ts-14) or {4 . . . 4} (remaining 36 Ts- 14)(anycombination set of numbers in a set is possible) Ts-19 64 15 kHz  32 *Ts (7 OS)Alt 1: {5, 5, 5, 5, 4, 4, 4} or {5, 5, 4, 5, 4, 5, 4} or {5, 4,5, 4, 5, 4, 5} or {4 times of 5 and 3 times of 4}Alt 2: {4, 4, 4, 4, 4,4, 4} (remaining 4 Ts-15) Or {3, 3, 2, 2, 2, 2, 2} (remaining of 16 Ts-15)or {2 . . . 2} (remaining of 18 Ts-15)Alt 3: {5, 5, 4, 5, 4, 5, 4} or{5, 4, 5, 4, 5, 4, 5} assuming 15 kHz subcarrier spacing of SC0 (e.g.128 FFT size) (any combination set of numbers in a set is possible)Ts-20 32 15 kHz  64 * Ts (7 OS)Alt 1: {3, 3, 2, 2, 2, 2, 2} or {3, 2, 2,3, 2, 2, 2} or {3, 2, 2, 2, 2, 2, 3} or (any combination of 2 times of 3and 4 times of 2) Alt 2: {2 . . . 2} (remaining of 2 Ts-16) or {2, 1 . .. 1} (remaining of 8 Ts-16) or {1, 1 . . . 1} (remaining of 8 Ts-16)Alt3: {3, 2, 2, 3, 2, 2, 2} or {2, 3, 2, 2, 3, 2, 2} assuming 15 kHzsubcarrier spacing of SC0 (e.g. 128 FFT size or 64 FFT size) Ts-21 12830 kHz  16 * Ts (7 OS)Alt 1: {10, 9, 9, 9, 9, 9, 9}Alt 2: {9 . . . 9}(remaining 1 Ts-14) or {5, 5, 5, 5, 4, 4, 4} (remaining 32 Ts-14) or {4,.., 4} (remaining 36 Ts- 14)Alt 3: {10, 10, 9, 9, 9, 9, 9, 9, 9, 9, 9,9, 9, 9} (14 OS) assuming 15 kHz subcarrier spacing of SC0(anycombination set of numbers in a set is possible) Ts-22 64 30 kHz  32 *Ts (7 OS)Alt 1: {5, 5, 5, 5, 4, 4, 4} or {5, 5, 4, 5, 4, 5, 4} or {5, 4,5, 4, 5, 4, 5} or {4 times of 5 and 3 times of 4}Alt 2: {4, 4, 4, 4, 4,4, 4} (remaining 4 Ts-15) Or {3, 3, 2, 2, 2, 2, 2} (remaining of 16 Ts-15) or {2 . . . 2} (remaining of 18 Ts-15)Alt 3: {5, 5, 5, 4, 5, 4, 5,4, 5, 4, 5, 4, 5, 4} or {5, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5}assuming 15 kHz subcarrier spacing of SC0 (some other combinations arealso possible, e.g. switching 4, 5 to 5, 4 in any number of places)(14OS) (any combination set of numbers in a set is possible) Ts-23 32 30kHz  64 * Ts (7 OS)Alt 1: {3, 3, 2, 2, 2, 2, 2} or {3, 2, 2, 3, 2, 2, 2}or {3, 2, 2, 2, 2, 2, 3} or (any combination of 2 times of 3 and 4 timesof 2)Alt 2: {2 . . . 2} (remaining of 2 Ts-16) or {2, 1 . . . 1}(remaining of 8 Ts-16) or {1, 1 . . . 1} (remaining of 8 Ts-16)Alt 3:{3, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2, 2, 3, 2} or {3, 2, 2, 3, 2, 2, 2, 3,2, 2, 2, 3, 2, 2} assuming 15 kHz subcarrier spacing of SC0 (some othercombinations are also possible, e.g. switching 2, 2, 3, 2 to 2, 3, 2, 2(or 3, 2, 2, 2) in any number of places) (14 OS) (any combination set ofnumbers in a set is possible) Ts-24 128 60 kHz  16 * Ts (7 OS)Alt 1:{10, 9, 9, 9, 9, 9, 9}Alt 2: {9 . . . 9} (remaining 1 Ts-14) or {5, 5,5, 5, 4, 4, 4} (remaining 32 Ts-14) or {4 . . . 4} (remaining 36 Ts-14)Alt 3: For 60 kHz subcarrier spacing and 128 FFT size, {10, 10, 10,10, 9, 9, 9} {9, 9, 9, 9, 9, 9, 9} {9, 9, 9, 9, 9, 9, 9} {9, 9, 9, 9, 9,9, 9} from 1st slot to 4th slot (repeated in 28 OS) assuming 15 kHzsubcarrier spacing of SC0 (any combination set of numbers in a set ispossible) Ts-25 64 60 kHz  32 * Ts (7 OS)Alt 1: {5, 5, 5, 5, 4, 4, 4} or{5, 5, 4, 5, 4, 5, 4} or {5, 4, 5, 4 ,5, 4, 5} or {4 times of 5 and 3times of 4}Alt 2: {4, 4, 4, 4, 4, 4, 4} (remaining 4 Ts-15) Or {3, 3, 2,2, 2, 2, 2} (remaining of 16 Ts- 15) or {2 . . . 2} (remaining of 18Ts-15)Alt 3: For 60 kHz subcarrier spacing and 64 FFT size, {5, 5, 5, 5,5, 4, 5} {4, 5, 4, 5, 4, 5, 4} {5, 4, 5, 4, 5, 4, 5} {4, 5, 4, 5, 4, 5,4} or {5, 5, 5, 5, 4, 5, 4} {5, 4, 5, 4, 5, 4, 5} {4, 5, 4, 5, 4, 5, 4}{5, 4, 5, 4, 5, 4, 5} from 1st slot to 4th slot assuming 15 kHzsubcarrier spacing of SC0 (repeated in 28 OS) (some other combinationsare also possible, e.g. switching 4, 5 to 5, 4 in any number ofplaces)(any combination set of numbers in a set is possible) Ts-26 32 60kHz  64 * Ts (7 OS)Alt 1: {3, 3, 2, 2, 2, 2, 2} or {3, 2, 2, 3, 2, 2, 2}or {3, 2, 2, 2, 2, 2, 3} or (any combination of 2 times of 3 and 4 timesof 2)Alt 2: {2 . . . 2} (remaining of 2 Ts-16) or {2, 1 . . . 1}(remaining of 8 Ts-16) or {1, 1 . . . 1} (remaining of 8 Ts-16)Alt 3:For 60 kHz subcarrier spacing and 32 FFT size, {3, 2, 3, 2, 3, 2, 2} {2,3, 2, 2, 2, 3, 2} {2, 2, 3, 2, 2, 2, 3} {2, 2, 2, 3, 2, 2, 2} or {3, 2,3, 2, 2, 3, 2}, {2, 2, 3, 2, 2, 2, 3} {2, 2, 2, 3, 2, 2, 2} {3, 2, 2, 2,3, 2, 2} from 1st slot to 4th slot assuming 15 kHz subcarrier spacing ofSC0 (repeated in 28 OS) (some other combinations are also possible, e.g.switching 2, 2, 3, 2 to 2, 3, 2, 2 (or 3, 2, 2, 2) in any number ofplaces)(any combination set of numbers in a set is possible)

Two cases may be considered. First case is that the same FFT size isassumed. Thus, sampling rate may linearly increase with subcarrierspacing. The second case is that the same sampling rate is kept, i.e.FFT size is reduced. In the description below, CP1 is the larger CP inTs-x per each case (assuming Ts-x is for the reference subcarrierspacing) based on the CP length). For example, CP1=160 with 15 kHzsubcarrier spacing and 2048 FFT size, CP1=160 with 30 kHz subcarrierspacing and 2048 FFT size, CP1=80 with 30 kHz subcarrier spacing and1024 FFT size). And, CP2 is the smaller CP in Ts-x per each case. Inother words, CP1 may be the CP length of special OS, and CP 2 may beused for the rest OSs.

(1) First case: Same FFT size is assumed.

FIG. 6 shows an example of CP lengths according to an embodiment of thepresent invention. Referring to FIG. 6, different subcarrier spacingand/or numerology is aligned at symbol level. The reference subcarrierspacing may be assumed as 15 kHz. In 15 kHz subcarrier spacing (SC0, CPlengths can be constructed such that the first OS has CP1 and theremaining OSs (6 OSs) have CP2. In 30 kHz subcarrier spacing(SC0*2=SC1), CP length can be constructed such that the first and secondOSs have CP1/2 and the remaining OSs (12 OSs) have CP2/2. In 60 kHzsubcarrier spacing (SC0*4=SC2), CP length can be constructed such thatthe first to fourth OSs have CP1/4 and the remaining OSs (24 OSs) haveCP2/4. In 7.5 kHz subcarrier spacing (SC0/2), CP length can beconstructed such that the first OSs has CP1+CP2 and the remaining OSshave CP2*2. In 3.75 kHz subcarrier spacing (SC0/4), CP length can beconstructed such that the first OSs has CP1+3*CP2 and the remaining OSshave CP2*4. In this case, options of CP length may be represented byTable 3 below.

TABLE 3 Subcarrier spacing CP length 15 kHz or CP1 (SC0), CP2 (SC0), CP2(SC0), CP2 (SC0), CP2 (SC0), CP2 SC0(Reference (SC0), CP2 (SC0), (repeatin every 7 OS) subcarrier spacing) 30 kHz or SC0*2 {CP1 (SC0), CP1(SC0), CP2 (SC0) . . . CP2 (SC0)} (two times of CP1, twelve times ofCP2) (repeat in every 14 OS) 60 kHz or SC0*4 {CP1 (SC0), CP1 (SC0), CP1(SC0), CP1 (SC0), CP2 (SC0) . . . CP2 (SC0)} (four times of CP1, 24times of CP2) (repeat in every 28 OS) 120 kHz or SC0*8 {CP1 (SC0) . . .CP1 (SC0), CP2 (SC0) . . . CP2 (SC0)} (8 times of CP1, 48 times of CP2)(repeat in every 56 OS) 7.5 kHz or SC0/2 {160 + 144, 144 + 144, 144 +144, 160 + 144, 144 + 144, 144 + 144, 144 + 144 assuming 2048 FFTsize{(CP1 (SC0) + CP2(SC0))/2, (CP2(SC0) + CP2(SC0)/2), (CP2(SC0) +CP2(SC0)/2), (CP1 (SC0) + CP2(SC0))/2, (CP2(SC0) + CP2(SC0)/2),(CP2(SC0) + CP2(SC0)/2), (CP2(SC0) + CP2(SC0)/2)} 3.75 kHz or SC0/4160 + 144 + 144 + 144, 144 + 144 + 144 + 160, 144 + 144 + 144 + 144,144 + 144 + 160 + 144, 144 + 144 + 144 + 144, 144 + 160 + 144 + 144,144 + 144 + 144 + 144 assuming 2048 FFT size (160 and 144 can bereplaced by CP1 (SC0) and CP2 (SC0))

Table 4 shows an example of CP length according to a subcarrier spacing,which is more detailed than Table 3 based on LTE as reference.

TABLE 4 FFT Subcarrier size spacing In Ts CP length in normal CP in Tsof LTE Ts-1 2048 15 kHz Ts {160, 144, 144, 144, 144, 144, 144} Ts-3 204830 kHz Ts/2 {80, 80, 72, 72, 72, 72, 72} in even slot{72, 72, 72, 72,72, 72, 72} in odd slot Ts-6 2048 60 kHz Ts/4 {40, 40, 40, 40, 36, 36,36} in first slot{36, 36, 36, 36, 36, 36, 36} from second to fourth slotTs-10 2048 7.5 kHz  2 *Ts {304, 288, 288, 304, 288, 288, 288} Ts-13 20483.75 kHz  4* Ts {592, 592, 576, 592, 576, 592, 576} Ts-15 64 3.75 kHz128 * Ts {640, 640, 640, 640, 512, 512, 512} or any combination of 4times of 640 and 3 times of 512

FIG. 7 shows another example of CP lengths according to an embodiment ofthe present invention. Referring to FIG. 7, different subcarrier spacingand/or numerology is aligned at slot or subframe level. In this case,options of CP length may be represented by Table 5 below.

TABLE 5 Subcarrier spacing CP length 15 kHz or {CP1 (SC0), CP2 (SC0),CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2 SC0(Reference (SC0), CP2 (SC0)}(repeat in every 7 OS) subcarrier spacing) 30 kHz or {CP1 (SC0), CP1(SC0), CP2 (SC0) . . . CP2 (SC0)} (two times of CP1, SC0*2 twelve timesof CP2) (repeat in every 14 OS) or {CP1 (SC0) + CP1-CP2 (SC0), CP2 (SC0). . . CP2 (SC0)} (repeat in every 14 OS) 60 kHz or {CP1 (SC0), CP1(SC0), CP1 (SC0), CP1 (SC0), CP2 (SC0) . . . CP2 SC0*4 (SC0)} (fourtimes of CP1, 24 times of CP2) (repeat in every 28 OS) or {CP1 (SC0) + 3*(CP1-CP2 (SC0)), CP2 (SC0) . . .}{one times of large CP with 27 CP2}(repeat in every 28 OS), or {CP1 (SC0) + 2*(CP1-CP2 (SC0)), CP1 (SC0) +2*(CP1-CP2 (SC0)), CP2 (SC0) . . .}(repeat in every 28 OS) 120 kHz or{CP1 (SC0) . . . CP1 (SC0), CP2 (SC0) . . . CP2 (SC0)} (8 times of CP1,SC0*8 48 times of CP2) (repeat in every 56 OS), 8 times of {CP1-CP2} canbe distributed in different OS 7.5 kHz or {CP1 (SC0), CP2 (SC0), CP2(SC0), CP2 (SC0), CP2 (SC0), CP2 SC0/2 (SC0), CP2 (SC0)} (repeat inevery 7 OS) 3.75 kHz or {CP1 (SC0), CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2(SC0), CP2 SC0/4 (SC0), CP2 (SC0)} (repeat in every 7 OS)

Table 6 shows options of CP length for a nested frame structure in aslot/subframe level alignment only. Any combination of base CP optionmay be possible in this option.

TABLE 6 Subcarrier spacing CP length 15 kHz or {CP1 (SC0), CP2 (SC0),CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2 SC0(Reference (SC0), CP2 (SC0)}(repeat in every 7 OS) subcarrier spacing) 30 kHz or {CP1 (SC0), CP2(SC0), CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2 SC0*2 (SC0), CP2 (SC0)}/2(repeat in every 7 OS) 60 kHz or {CP1 (SC0), CP2 (SC0), CP2 (SC0), CP2(SC0), CP2 (SC0), CP2 SC0*4 (SC0), CP2 (SC0)}/4 (repeat in every 7 OS)120 kHz or {CP1 (SC0), CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2SC0*8 (SC0), CP2 (SC0)}/8 (repeat in every 7 OS) 7.5 kHz or {CP1 (SC0),CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2 SC0/2 (SC0), CP2(SC0)}*2 or {CP1 (SC0), CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2(SC0), CP2 (SC0)} (repeat in every 7 OS) (repeat in every 7 OS) 3.75 kHzor {CP1 (SC0), CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2 SC0/4(SC0), CP2 (SC0)}*4 or {CP1 (SC0), CP2 (SC0), CP2 (SC0), CP2 (SC0), CP2(SC0), CP2 (SC0), CP2 (SC0)} *2 or {CP1 (SC0), CP2 (SC0), CP2 (SC0), CP2(SC0), CP2 (SC0), CP2 (SC0), CP2 (SC0)} *2 (repeat in every 7 OS)(repeat in every 7 OS)

When different subcarrier spacing and/or numerology is aligned atmultiple slot/subframe level, any set from Table 2 may be used.

(2) Second case: FFT size is reduced for larger subcarrier spacing (i.e.the same sampling rate is assumed)

In this case, CP1 (SC0) may be replaced by CP1 (SC0)/m, where m is FFTsize of SC0/FFT size of SC1 (assuming 2̂m scale) in the first case.Further, it may be assumed that 1.4 MHz bandwidth with 128 FFT size isused for 15 kHz subcarrier spacing. Further, alignment among differentnumerologies may be met in multiple subframe levels in this case.

Followings are examples.

A. For 30 kHz subcarrier spacing

1) SF0: {10, 10, 9, 9, 9, 9, 9}/SF1: {9, 9, 9, 9, 9, 9, 9}

2) SF0: {11, 9, 9, 9, 9, 9, 9}/SF1: {9, 9, 9, 9, 9, 9, 9}.

3) Not align subframe boundaries with the slot boundaries of 15 kHzsubcarrier spacing

SF0: {10, 9, 9, 9, 9, 9, 9}/SF1: {10, 9, 9, 9, 9, 9, 9}

B. For 60 kHz subcarrier spacing

1) SF0: {10, 10, 10, 10, 9, 9, 9}/SF1: {9, 9, 9, 9, 9, 9, 9}/SF2: {9, 9,9, 9, 9, 9, 9}/SF3: {9, 9, 9, 9, 9, 9, 9}

2) SF0: {11, 11, 9, 9, 9, 9, 9}/SF1: {9, 9, 9, 9, 9, 9, 9}/SF2: {9, 9,9, 9, 9, 9, 9}/SF3: {9, 9, 9, 9, 9, 9, 9}

3) SF0: {13, 9, 9, 9, 9, 9, 9}/SF1: {9, 9, 9, 9, 9, 9, 9}/SF2: {9, 9, 9,9, 9, 9, 9}/SF3: {9, 9, 9, 9, 9, 9, 9}

4) SF0: {12, 10, 9, 9, 9, 9, 9}/SF1: {9, 9, 9, 9, 9, 9, 9}/SF2: {9, 9,9, 9, 9, 9, 9}/SF3: {9, 9, 9, 9, 9, 9, 9}

5) SF0: {10, 10, 9, 9, 9, 9, 9}/SF1: {10, 10, 9, 9, 9, 9, 9}/SF2: {9, 9,9, 9, 9, 9, 9}/SF3: {9, 9, 9, 9, 9, 9, 9}

6) SF0: {12, 9, 9, 9, 9, 9, 9}/SF1: {10, 9, 9, 9, 9, 9, 9}/SF2: {9, 9,9, 9, 9, 9, 9}/SF3: {9, 9, 9, 9, 9, 9, 9}

7) SF0: {11, 9, 9, 9, 9, 9, 9}/SF1: {11, 9, 9, 9, 9, 9, 9}/SF2: {9, 9,9, 9, 9, 9, 9}/SF3: {9, 9, 9, 9, 9, 9, 9}

8) Not align subframe boundaries with 30 kHz subcarrier spacing

SF0: {10, 9, 9, 9, 9, 9, 9}/SF1: {10, 9, 9, 9, 9, 9, 9}/SF2: {10, 9, 9,9, 9, 9, 9}/SF3: {10, 9, 9, 9, 9, 9, 9}

9) Not align subframe boundaries with 30 kHz subcarrier spacing

SF0: {10, 10, 9, 9, 9, 9, 9}/SF1: {9, 9, 9, 9, 9, 9, 9}/SF2: {10, 10, 9,9, 9, 9}/SF3: {9, 9, 9, 9, 9, 9, 9}

10) Not align subframe boundaries with 30 kHz subcarrier spacing

SF0: {11, 9, 9, 9, 9, 9, 9}/SF1: {9, 9, 9, 9, 9, 9, 9}/SF2: {11, 9, 9,9, 9, 9, 9}/SF3: {9, 9, 9, 9, 9, 9, 9}

11) Not align subframe boundaries with 30 kHz subcarrier spacing

SF0: {12, 9, 9, 9, 9, 9, 9}/SF1: {9, 9, 9, 9, 9, 9, 9}/SF2: {10, 9, 9,9, 9, 9, 9}/SF3: {9, 9, 9, 9, 9, 9, 9}

Considering options and approaches described above, Table 7 to Table 9shows slot structure for 15 kHz, 30 kHz and 60 kHz subcarrier spacing,respectively. In Table 7 to Table 9, the sampling rate may be assumed as30720(=15*2048) for all subcarrier spacing, like the current sample ratein 3GPP LTE. However, the sampling rate may be different from each otherfor different subcarrier spacing.

TABLE 7 CP CP CP CP CP CP CP 160 2048 144 2048 144 2048 144 2048 1442048 144 2048 144 2048

TABLE 8 Slot index CP CP CP CP CP CP CP 1) Option 1 Slot 80 1024 80 102472 1024 72 1024 72 1024 72 1024 72 1024 index % 2 = 0 Slot 72 1024 721024 72 1024 72 1024 72 1024 72 1024 72 1024 index % 2 = 1 2) Option 2Slot 88 1024 72 1024 72 1024 72 1024 72 1024 72 1024 72 1024 index % 2 =0 Slot 72 1024 72 1024 72 1024 72 1024 72 1024 72 1024 72 1024 index % 2= 1 3) Option 3 Slot 80 1024 72 1024 72 1024 72 1024 72 1024 72 1024 721024 index % 2 = 0 Slot 80 1024 72 1024 72 1024 72 1024 72 1024 72 102472 1024 index % 2 = 1

TABLE 9 Slot index CP CP CP CP CP CP CP 1) Option 1 Slot 40 512 40 51240 512 40 512 36 512 36 512 36 512 index % 4 = 0 Slot 36 512 36 512 36512 36 512 36 512 36 512 36 512 index % 4 = 1 Slot 36 512 36 512 36 51236 512 36 512 36 512 36 512 index % 4 = 2 Slot 36 512 36 512 36 512 36512 36 512 36 512 36 512 index % 4 = 3 2) Option 2 Slot 44 512 44 512 36512 36 512 36 512 36 512 36 512 index % 4 = 0 Slot 36 512 36 512 36 51236 512 36 512 36 512 36 512 index % 4 = 1 Slot 36 512 36 512 36 512 36512 36 512 36 512 36 512 index % 4 = 2 Slot 36 512 36 512 36 512 36 51236 512 36 512 36 512 index % 4 = 3 3) Option 3 Slot 52 512 36 512 36 51236 512 36 512 36 512 36 512 index % 4 = 0 Slot 36 512 36 512 36 512 36512 36 512 36 512 36 512 index % 4 = 1 Slot 36 512 36 512 36 512 36 51236 512 36 512 36 512 index % 4 = 2 Slot 36 512 36 512 36 512 36 512 36512 36 512 36 512 index % 4 = 3 4) Option 4 Slot 48 512 40 512 36 512 36512 36 512 36 512 36 512 index % 4 = 0 Slot 36 512 36 512 36 512 36 51236 512 36 512 36 512 index % 4 = 1 Slot 36 512 36 512 36 512 36 512 36512 36 512 36 512 index % 4 = 2 Slot 36 512 36 512 36 512 36 512 36 51236 512 36 512 index % 4 = 3 5) Option 5 Slot 40 512 40 512 36 512 36 51236 512 36 512 36 512 index % 4 = 0 Slot 40 512 40 512 36 512 36 512 36512 36 512 36 512 index % 4 = 1 Slot 36 512 36 512 36 512 36 512 36 51236 512 36 512 index % 4 = 2 Slot 36 512 36 512 36 512 36 512 36 512 36512 36 512 index % 4 = 3 6) Option 6 Slot 48 512 36 512 36 512 36 512 36512 36 512 36 512 index % 4 = 0 Slot 40 512 36 512 36 512 36 512 36 51236 512 36 512 index % 4 = 1 Slot 36 512 36 512 36 512 36 512 36 512 36512 36 512 index % 4 = 2 Slot 36 512 36 512 36 512 36 512 36 512 36 51236 512 index % 4 = 3 7) Option 7 Slot 44 512 36 512 36 512 36 512 36 51236 512 36 512 index % 4 = 0 Slot 44 512 36 512 36 512 36 512 36 512 36512 36 512 index % 4 = 1 Slot 36 512 36 512 36 512 36 512 36 512 36 51236 512 index % 4 = 2 Slot 36 512 36 512 36 512 36 512 36 512 36 512 36512 index % 4 = 3 8) Option 8 Slot 40 512 36 512 36 512 36 512 36 512 36512 36 512 index % 4 = 0 Slot 40 512 36 512 36 512 36 512 36 512 36 51236 512 index % 4 = 1 Slot 40 512 36 512 36 512 36 512 36 512 36 512 36512 index % 4 = 2 Slot 40 512 36 512 36 512 36 512 36 512 36 512 36 512index % 4 = 3 8) Option 9 Slot 44 512 36 512 36 512 36 512 36 512 36 51236 512 index % 4 = 0 Slot 36 512 36 512 36 512 36 512 36 512 36 512 36512 index % 4 = 1 Slot 44 512 36 512 36 512 36 512 36 512 36 512 36 512index % 4 = 2 Slot 36 512 36 512 36 512 36 512 36 512 36 512 36 512index % 4 = 3

2. Multiplexing different numerologies in a carrier

For supporting multiple different numerologies in a single carrier,multiple different levels of frequency division multiplexing (FDM) maybe considered.

FIG. 8 shows an example of multiplexing different numerologies in asingle carrier according to an embodiment of the present invention.Referring to FIG. 8, multiplexing based on the resource unit assumed forthe largest subcarrier spacing may be supported. That is, FDMmultiplexing may be supported at 1 ms level. In this case, the referencesubcarrier spacing may be 15 kHz.

FIG. 9 shows another example of multiplexing different numerologies in asingle carrier according to an embodiment of the present invention.Referring to FIG. 9, different numerologies and/or subcarrier spacingmay be multiplexed at slot level of reference subcarrier spacing orsubframe level of middle size subcarrier spacing.

FIG. 10 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention.Referring to FIG. 10, different numerologies and/or subcarrier spacingmay be multiplexed at subframe level or slot level of the largestsubcarrier spacing. In this case, the reference subcarrier spacing maybe 60 kHz.

Depending on multiplexing mechanism described above, frame structure maybe different. For example, if multiplexing mechanism shown in FIG. 8 isused, from the multiplexing perspective, it may be necessary to align k1TTIs of SC1 (15 kHz subcarrier spacing), k2 TTIs of SC2 (30 kHzsubcarrier spacing), and k3 TTIs of SC3 (60 kHz subcarrier spacing)within the subframe of SC1. For example, k1=1, k2=3 and k3=4. Withineach subframe of each subcarrier spacing, different mapping or differentshort TTI formation may be considered. If multiplexing mechanism shownin FIG. 9 is used, the alignment may be done at slot level rather thansubframe level or subframe of different reference subcarrier spacing (inthis case, the reference subcarrier spacing may be SC2). If multiplexingmechanism shown in FIG. 10 is used, multiplexing may be done at smallergranularity compared to others, which however requires a bit moreconsiderations on frame structure.

FIG. 11 shows an example of a frame structure considering multiplexingof different subcarrier spacing according to an embodiment of thepresent invention. Referring to FIG. 11, only alignment is done at 1 mslevel or subframe level of reference subcarrier spacing, andmini-subframe may be defined independently per different numerology.

FIG. 12 shows another example of a frame structure consideringmultiplexing of different subcarrier spacing according to an embodimentof the present invention. Referring to FIG. 12, mini-subframe length iskept as same regardless of numerology which leads different number ofOSs in a mini-subframe.

FIG. 13 shows another example of a frame structure consideringmultiplexing of different subcarrier spacing according to an embodimentof the present invention. Referring to FIG. 13, mini-subframe level atslot may be used for alignment among different numerologies.

FIG. 14 shows another example of a frame structure consideringmultiplexing of different subcarrier spacing according to an embodimentof the present invention. Referring to FIG. 14, mini-subframe (e.g. 2 OSof reference subcarrier spacing) is kept as same duration regardless ofnumerology which leads different number of OSs in different numerology,while subframe length may be scaled with subcarrier spacing.

In the description below, how to support efficiently more fast-scalemultiplexing (shown in FIG. 13 or FIG. 14), which mainly focusing onmultiplexing between SC1 (15 kHz subcarrier spacing), SC2 (30 kHzsubcarrier spacing) and SC3 (60 kHz subcarrier spacing), is mainlyaddressed. Even though not mentioned, SC0 may be 3.75 kHz subcarrierspacing or 7.5 kHz subcarrier spacing. It may be generally assumed thatmultiplexing between 15 kHz, 7.5 kHz and 3.75 kHz is based on 15 kHzsubcarrier spacing. Thus, potentially two reference subcarrier spacingmay be used if all subcarrier spacing of 3.75 kHz, 7.5 kHz, 15 kHz, 30kHz, and 60 kHz are multiplexed. Further, if short TTI is applied to3.75 kHz subcarrier spacing or 7.5 kHz subcarrier spacing, the conceptmentioned in the present invention may be generally applied. However,the reference subcarrier spacing for CP formation and TTI lengthformation may be different from each other. For example, referencesubcarrier spacing for CP formation may be 15 kHz subcarrier spacing,whereas reference subcarrier spacing for TTI formation may be 60 kHzsubcarrier spacing. To avoid confusion, reference subcarrier spacingmentioned in the present invention refers the latter, and two values maybe different from each other depending on the approaches.

In multiplexing different numerologies in the same frequency withdifferent short TTI (sTTI) length, and so on, among different subcarrierspacing, some considerations should be given. In terms of sTTI length,the absolute time may be same regardless of subcarrier spacing which maydetermine different OSs in a sTTI. If the minimum length of sTTI issupported in SC1 which is the reference subcarrier spacing, then, lengthof SC2 and SC3 (assuming SC2=2*SC1, SC3=4*SC1) may become 2 times and 4times of sTTI length of SC1. More generally, if SC2=m*SC1, the sTTIlength may become m*SC1, and if SC3=n*SC1, sTTI length of SC3 may becomen*SC1. In this case, if sTTI length of SC1 is ‘k’ OFDM symbols, sTTIlength of SC2 may become k*m, and that of SC3 may become k*n.

FIG. 15 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention. Inthis embodiment, it is assumed that k=1 or 2. This is to align amongdifferent subcarrier spacing, and multiplex different sTTIs withdifferent numerologies. Referring to FIG. 15, minimum time unit tomultiplex different numerology may be ‘k’ OFDM symbols based on SC1.

FIG. 16 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention. Inthis embodiment, it is assumed that k=3 or 4. Further shorter TTI withina numerology may be considered. For example, for SC3, furtherpartitioning of 12 OS into 3*4 OS sTTIs or 6*2 OS sTTIs may beconsidered.

FIG. 17 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention.This frame structure may be necessary in case that flexible multiplexingamong different numerologies at mini-subframe level or shorter TTI levelis necessary. In this case, OSs between two sTTIs are overlapped to havethe uniform value of ‘k’.

Another example of linearly scale version of sTTI may be to define sTTIwith SC3 of k1 OS, and SC1 of k1/(n/m) OS as a basic unit of sTTI andSC2 of k1/n OS. For example, if SC3=4*SC1, and SC2=2*SC1, and sTTIlength of SC3 is 4 OS, sTTI length may become 2 OS in SC2, and 1 OS inSC1. k1 may be used for slot. There may be odd number of slots in 1 msin SC3 (e.g. assuming 60 kHz subcarrier spacing, there are 7 slots in 1ms), and one subframe may consist of two slots which is 8 OS in total.Then, one subframe in SC3 may consist of 8 OS, one subframe in SC2 mayconsist of 4 OS, and one subframe in SC1 may consist of 2 OS. Onesubframe in SC3 may span over 1 ms boundary, So, 2 ms may be consideredas a basic unit of multiplexing duration and, minimum size ofmultiplexing different numerology may be one subframe of the shortestTTI or the largest subcarrier spacing (i.e. 8*OS in SC3 in thisexample).

In summary, to support the frame structure, different approaches may beconsidered as follows.

-   -   Basic subframe length may be fixed per each subcarrier spacing,        assuming minimum ‘k’ of a reference subcarrier spacing which is        used for multiplexing guideline. For example, a reference        subcarrier spacing may be 15 kHz or may be configured by higher        layer. Basic subframe length of SCi may be defined as k*m, where        SCi=SC0*m (SC0 is the reference subcarrier spacing). As        mentioned described above, further dividing into shorter TTI        within SCi may also be allowed, which is particularly useful in        case that k*m is large.    -   Subframe length of each subcarrier spacing may be defined as ‘L’        OS in SC which is used for physical mapping for channels, data,        etc. If multiplexing is enabled at short TTI level, mapping may        become different.    -   Basic subframe length may be fixed based on the shortest TTI or        the largest subcarrier spacing supported in the same carrier,        and may be scaled up based on OS length. This may be used only        for multiplexing purpose, and channel mapping may be different        per each subcarrier spacing, depending on whether sTTI is used        for multiplexing purpose or not. For example, based on        SC3=4*SC0, it may be assumed that subframe in SC3 consists of 16        OS, subframe in SC2 consists of 8 OS, and subframe in SC1        consists of 4 OS. For another example, with 15 kHz subcarrier        spacing as the reference subcarrier spacing, over 2 ms, there        may be 7 subframes of SC3/SC2/SC1 and minimum multiplexing size        may become 16 OSs in SC3. For SC2 and SC1, this mapping may only        be used if sTTI is configured in each subcarrier spacing (or        multiplexing is enabled by higher layer configuration).

Another specific example is to define subframe for 60 kHz subcarrierspacing as 8 OS, for 30 kHz subcarrier spacing as 7 OS, for 15 kHzsubcarrier spacing for 7 OS, and define the short TTI as follows.

-   -   In 60 kHz subcarrier spacing, 2 or 4 OS sTTIs may be considered.    -   In 30 kHz subcarrier spacing, 2 or 4 OS sTTIs may be considered        which may be spanning over multiple subframes of 30 kHz        subcarrier spacing.    -   In 15 kHz subcarrier spacing, 2 or 4 OS sTTIs may be considered        which may be spanning over multiple subframe of 15 kHz        subcarrier spacing.

FIG. 18 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention.Referring to FIG. 18, subframe for the largest subcarrier spacing usedfor multiplexing may be used as a reference to define sTTI length ofsmaller subcarrier spacing numerologies. If extended CP is used,subframe in SC3 may consists of 12 OS. Thus, sTTI length in SC2 is 6 OS,and sTTI length in SC1 is 3 OS, respectively.

FIG. 19 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention.Referring to FIG. 19, it may be assumed that reference subcarrierspacing is 15 kHz. In this embodiment, subframe and/or mini-subframeand/or slot of each numerology is aligned withminisubframe/slot/subframe of numerology of the reference subcarrierspacing (or SC0). For SC0, three different TTI length may be provided:k1 OS, k2 OS, k3 OS (for example, k1=2, k2=7, k3=14). For SC1=SC0*2, twodifferent TTI length may be provided: k1*2 OS, k2*2 OS. For SC2=SC0*4,one TTI length may be provided: k1*4 OS. This approach may be extendedto general cases, and 15 kHz may be replaced by reference subcarrierspacing SC0 (i.e. 30 kHz and 60 kHz may be replaced by 2*SC0 and 4*SC0,respectively).

As described above, different TTIs are provided based on the basenumerology used in a carrier. The base numerology may be defined byprimary cell (PCell) numerology when carrier aggregation (CA) isconfigured. For example, if 4 GHz carrier and 30 GHz carrier areaggregated and 4 GHz carrier carries synchronization signal based on 30kHz subcarrier spacing and 30 GHz carrier based on 60 kHz subcarrierspacing, the TTI length for PCell, i.e. 4 GHz carrier, may be 0.5 ms,0.25 ms, 0.5/7 ms, and TTI length for secondary cell (SCell), i.e. 30GHz carrier, may be 0.25 ms, 0.5/7 ms. This is to align betweendifferent numerologies.

This may allow a carrier to have different numerology depending on theoperation or per UE. For example, it may be assumed that there is acarrier with 30 GHz frequency with 60 kHz subcarrier spacing usingnormal CP as a base numerology. If there are two UEs, one UE may beconnected to the carrier as a SCell and the other UE may be connected tothe carrier as a PCell. In this case, the subframe for the given carriermay be as follows.

-   -   For the UE connected as SCell and PCell utilizes 15 kHz        subcarrier spacing as base numerology, one subframe may consist        of 8 OS.    -   For the UE connected as PCell, one subframe may consist of 14        OS.

When different subframe lengths are supported, it may impact thescheduling complexity. To address this issue, one approach may be to fixsubframe per subcarrier spacing, regardless of PCell or SCell. In thiscase, if a carrier operates with 60 kHz subcarrier spacing, regardlessof PCell/SCell, subframe length may always be 8 OSs. Further, schedulingover multiple subframe may be supported. Alternatively, the subframelength may be indicated by physical broadcast channel (PBCH).

FIG. 20 shows another example of multiplexing different numerologies ina single carrier according to an embodiment of the present invention.Referring to FIG. 20, subframe length may be defined by scaling down persubcarrier spacing, and virtual mini-subframe may be created which mayhave the same absolute time. For example, if two mini-subframe size of 2OSs and 1 OS are considered for base numerology in SC0, 4 OSs and 2 OSsfor SC0*2, 8 OSs and 4 OSs for SC0*4 may be considered, respectively.

In this case, mini-subframe of larger subcarrier spacing may be spannedover different subframe to be aligned with lower or base numerologysymbol/mini-subframe boundaries. In other words, different sets ofsubframe length may be defined. Subframe may be defined as 7 or 14 OSs,and mini-subframe may be defined as 1*k or 2*k or m*k OS, wherek=SCk/SC0 (SCk is the corresponding subcarrier spacing and SC0 is thereference subcarrier spacing), and m is a size of mini-subframe whichmay be supported by the base numerology, may be configurable.

3. Subframe indexing

When different numerology is mixed in the same time/frequency resourcewith multiple levels of subframe, how to index and how to mapmini-subframe and scheduling may need to be clarified. For example, atleast one of the following options may be considered at least for PCellbase numerology.

(1) Alt 1: Constant number of OS in a subframe may be used. Subframelength may be defined based on numerology searched via initial cellaccess procedure. Within a 1 ms or 10 ms, there may be different numberof subframes depending on numerology. For example, 15 kHz subcarrierspacing may lead 1 subframe, 30 kHz subcarrier spacing may lead 2subframe, and so on. For 7.5 kHz and 3.75 kHz subcarrier spacing, it maybe further considered that only 5 and 2.5 subframes may be present in 10ms or it may be assumed that subframe is kept as same to thosenumerologies and the number of effective symbols may change. In terms ofOS index, OS index may be based on subframe, and OS index (e.g. 0, 1 . .. 13 or 0, 1 . . . 6, 0, 1 . . . 6) in a subframe may be used similar toLTE.

(2) Subframe may be defined by 1 (or k) ms, which then leads differentnumber of OSs in a subframe depending on numerology. In this case,another indexing on mini-subframe or sub-subframe may be necessary forsubcarrier spacing larger than 15 kHz, and another indexing onsuper-subframe or subframe-group may also be necessary for subcarrierspacing smaller than 15 kHz. For 3.75 kHz, it may be assumed that thereare only three OS in 1 ms by either extending CP length or reserve sometime duration for some other purpose.

FIG. 21 shows an example of subframe indexing for different numerologiesaccording to an embodiment of the present invention. This embodimentcorresponds to option (2) described above. In terms of OS index, twoapproaches may be considered. If mini-subframe is used, OS index may bebased on subframe and separate mini-subframe index may be used.Alternatively, if mini-subframe is always defined (regardless of usage),OS index may be defined based on mini-subframe.

For SCell base numerology, either option (1) or option (2) may be used,and mini-subframe of SCell may be aligned with mini-subframe of PCellwith option (2). OS index may be used differently depending on PCell orSCell, if OS index is based on mini-subframe.

FIG. 22 shows another example of subframe indexing for differentnumerologies according to an embodiment of the present invention. Ifdifferent numerology is used in a carrier in in-band mode, it may bedesirable to align with host numerology. In this case, option (2) likealignment may seem a natural choice, and k ms may defined by thesubframe length of base numerology. In other words, no separate subframemay be defined for the numerology multiplexed in-band with hostnumerology. Instead, mini-subframe (for subcarrier spacing larger thanhost numerology) or subframe-group (for subcarrier spacing smaller thanhost numerology) may be defined.

In other words, subframe/OS index may be determined for different casesas follows.

(1) For PCell, subframe/OS index may be determined based on basenumerology (assuming that base numerology is the numerology used forsynchronization process).

A. Subframe may be defined by K OSs (e.g. K=14 with normal CP, K=12 withextended CP).

B. Mini-subframe may be pre-defined or configured by the systeminformation.

Mini-subframe may be defined by K1 OSs (e.g. K1=1 or K1=2). If K1=1, OSindex of base numerology may be used for mini-subframe index for in-bandmultiplexed numerologies and base numerology.

(2) For PCell/SCell, subframe/OS index may be determined based onin-band multiplexed different numerology SCi (e.g. for URLLC ormultimedia broadcast multicast services (MBMS) or mMTC).

A. Subframe may be defined by K OSs of base numerology of the hostcarrier. For example, if the numerology used for URLLC is 60 kHzsubcarrier spacing, whereas host carrier uses 15 kHz subcarrier spacing,subframe may be defined as 1 ms with 14 OSs of 15 kHz subcarrierspacing. If MBMS with 2.5 kHz subcarrier spacing is used, still 1 mswith 14 OSs based on 15 kHz subcarrier spacing may be used.

B. If SCi>SC0, mini-subframe may be defined by floor (K1*(SCi/SC0)) OSsbased on SCi. For example, if the numerology used for URLLC is 60 kHzsubcarrier spacing whereas host carrier uses 15 kHz subcarrier spacing,mini-subframe may be defined as 8 OSs or 4 OSs (if K1=1 or K1=2). Interms of OS index in SCi, OS index within a mini-subframe may be used ifmini-subframe is defined. Otherwise, OS index within 1 subframe of basenumerology may be used. The number of OS may be larger than 14, e.g.with 60 kHz subcarrier spacing, OS index may be 0, 1, 2, 3 . . . 55 orthere may be 8 slots with OS index from 0, 1 . . . 6.

C. If SCi<SC0, a subframe group may be defined over floor (SC0/SCi)subframes (if necessary). In terms of OS index in SCi, OS index within asubframe group may be used if subframe group is defined. Alternatively,OS index in a subframe of base numerology may be used.

(3) For SCell, subframe/OS index may be determined based on basenumerology SC0_SC where PCell base numerology is SC0_PC.

A. SCell OS index and/or subframe may be derived as if the cell is PCell(i.e. follow option (1) above).

B. SCell OS index and/or subframe may be derived as if the cell isin-band operation (i.e. follow option (2) above)

C. If the same use case is the target for PCell/SCell, option Adescribed above may be used. If SCell is for different use case, optionB described above may be used.

D. Both subframe and mini-subframe or subframe-group may be defined forSCell. That is, option A and B described above may be used at the sametime.

E. If cross-carrier scheduling is used, option B described above may be.Alternatively, option A described above may be used as a baseline, andoption B described above may be used additionally. Otherwise, option Adescribed above may be used.

To align the number of frames/subframes, maximum time duration thatframe index can represent may be linearly scaled up or down depending onsubcarrier spacing. For example, if frame index is from 0 . . . 1023with 15 kHz subcarrier spacing, 1024 ms may be represented, and with 30kHz subcarrier spacing, 512 ms may be represented, and with 3.75 kHzsubcarrier spacing, 4096 ms may be represented. In other words, allframe structure may be linearly scaled down or up for the basenumerology.

When different numerology is carrier-aggregated, timer and relatedtiming may follow its own subframe definition or may be configured tofollow PCell numerology/timing in case there is dependency or configuredto do so. For example, if measurement gap is configured, the timing mayfollow PCell numerology/timing as the gap is common to PCell and SCell.In this case, timer which is independent may follow SCellnumerology/timing. If this approach is applied to both PCell/SCell,PCell numerology/timing may be used. If it is independent, each cell'snumerology/timing may be used.

4. MBMS numerology options

Depending on coverage and channel environments, the required CP lengthmay be different to support MBMS. The shortest CP length may be as smallas normal CP with a given subcarrier spacing (i.e. about 7% CP overhead)up to 200 us. To increase CP length, the overall two approaches may beconsidered, one of which is to decrease subcarrier spacing and the otheris to increase CP length with keeping subcarrier spacing.

To allow efficient multiplexing between unicast and multicast in bothTDM and

FDM, it may be necessary to align MBMS numerology with different sTTIsize of unicast. For example, it may be assumed that a subcarrierspacing used for unicast is SC0 with normal CP, and the sTTI lengthsupported by the unicast may be m0*SC0, ml*SC0, m2*SC0 . . . mk−1*SC0(e.g. m0=2, m1=7 or one slot, mk−1=14). Depending on CP lengthrequirement of MBMS, it may or may not be easily possible to align withall sTTI lengths. The sTTI length may be realized by increasingsubcarrier spacing with larger number of OSs while keeping the absolutetime as same. For example, instead of m0*SC0, m0*SC0*K may also beconsidered.

With assumption that SC0=15 kHz, the present invention discussessupportable CP length and possible alignment options. Without loss ofgenerality, it may be expanded to other subcarrier spacing values andthe number may be linearly reduced by K, where SCi=SC0*K.

(1) Aligned at m0: Basic principle is to use SCi of MBMS as SCi=SC0/m0,and CPs of m0 symbols in SC0 may be added to create one CP for SCi. Forexample, if m0 is 2, SCi=7.5 kHz, and CP length for SCi is 144+144 Ts(in SC0). For the handling of larger CP in SC0, the approaches describedin the present invention may be applied (e.g. reserve for some otherpurpose, or absorb in the first OS, etc.). If m0>2, more than one OS inSCi may be considered.

(2) Aligned at ml: Assuming ml is either 7 OSs or one slot, alignmentmay become a bit tricky, as 7 cannot be divided into 2 or 4 or 8. Oneexample to utilize this option is to start from extended CP option forSC0 where 6 OS with equal sized CP length is assumed, and try to alignMBMS CP to it. For example, if this option is used, one of SCi=SC0/6,SCi=SC0/3, SCi=SC0/2 (in addition to SCi=SC0) may be supported, and theCP length for each option may be 6*512 Ts, 3*512 Ts, 2*512 Ts,respectively (i.e. 6 times of extended CP, 3 times of extended CP, 2times of extended CP, respectively).

(3) Aligned at mk−1: MBMS numerology may be aligned with a subframe inSC0. Similar to option (2), first option is to consider aligning withextended CP in SC0, i.e. SCi=SC0/12, SCi=SC0/6, SCi=SC0/4, SCi=SC0/3,SCi=SC0/2 (in addition to SCi=SC0) may be supported, and the CP lengthfor each option may be 12*512 Ts, 6*512 Ts, 4*512 Ts, 3*512 Ts, 2*512Ts, respectively (i.e. 12 times of extended CP, 6 times of extended CP,4 times of extended CP, 3 times of extended CP, 2 times of extended CP,respectively).

This shows a possibility of aligning sTTI of MBMS numerology withreference/host numerology. If sTTI size is too small (e.g. only a fewOSs) for MBMS, alignment between host numerology and MBMS numerology mayoccur in a multiple subframe level (e.g. 2 or 4 subframe of hostsubframe). Accordingly, multiple of sTTI may be used as a baseline forMBMS operation. More specifically, the following example may beconsidered assuming that base numerology is 15 kHz subcarrier spacing.Each pair represents CP length, subcarrier spacing, the number of OSs ina TTI for MBMS. Similarly, for different reference subcarrier spacing(30 kHz or 60 kHz), the scale may be applied by replacing 15 kHz with 30kHz or 60 kHz.

-   -   15 kHz extended CP length*12, 15/12 kHz, 4 or 8 (align at 4 or 8        subframes level)    -   15 kHz extended CP length*6, 15/6 kHz, 4 or 8 (align at 2 or 4        subframes level)    -   15 kHz extended CP length*4, 15/4 kHz, 3 or 6 (align at 1 or 2        subframes level)    -   15 kHz extended CP length*3, 15/3 kHz, 4 or 8 (align at 1 or 2        subframes level)    -   15 kHz extended CP length*1, 15/1 kHz, 12 (align at 1 subframes        level)    -   15 kHz normal CP length*2, 15/2 kHz, 7 (align at 1 subframes        level)    -   15 kHz normal CP length*4, 15/4 kHz, 7 or 14 (align at 2 or 4        subframes level)    -   15 kHz normal CP length*7, 15/7 kHz, 4 or 8 (align at 2 or 4        subframes level)

FIG. 23 shows a method for configuring a frame by a network nodeaccording to an embodiment of the present invention. The presentinvention described above may be applied to this embodiment.

In step S100, the network node configures a frame in which a first CP isallocated to a first symbol in every 0.5 ms and a second CP is allocatedto remaining symbols in every 0.5 ms. In step S110, the network nodecommunicates with a user equipment (UE) by using the frame. A length ofthe first CP is longer than a length of the second CP.

The length of the first CP and the length of the second CP, in terms ofsampling time, may depend on a subcarrier spacing.

The frame may be a first frame with a first subcarrier spacing, and thefirst subcarrier spacing may be a reference subcarrier spacing. In thiscase, the first frame consists of 7 OSs based on the referencesubcarrier spacing. Further, the network node may configures a secondframe with a second subcarrier spacing. The second subcarrier spacingmay be power of 2 for the first subcarrier spacing. The first frame andthe second frame may be aligned with each other at OFDM symbol level orslot level or subframe level

FIG. 24 shows a wireless communication system to implement an embodimentof the present invention.

A network node 800 includes a processor 810, a memory 820 and atransceiver 830.

The processor 810 may be configured to implement proposed functions,procedures and/or methods described in this description. Layers of theradio interface protocol may be implemented in the processor 810. Thememory 820 is operatively coupled with the processor 810 and stores avariety of information to operate the processor 810. The transceiver 830is operatively coupled with the processor 810, and transmits and/orreceives a radio signal.

A UE 900 includes a processor 910, a memory 920 and a transceiver 930.The processor 910 may be configured to implement proposed functions,procedures and/or methods described in this description. Layers of theradio interface protocol may be implemented in the processor 910. Thememory 920 is operatively coupled with the processor 910 and stores avariety of information to operate the processor 910. The transceiver 930is operatively coupled with the processor 910, and transmits and/orreceives a radio signal.

The processors 810, 910 may include application-specific integratedcircuit (ASIC), other chipset, logic circuit and/or data processingdevice. The memories 820, 920 may include read-only memory (ROM), randomaccess memory (RAM), flash memory, memory card, storage medium and/orother storage device. The transceivers 830, 930 may include basebandcircuitry to process radio frequency signals. When the embodiments areimplemented in software, the techniques described herein can beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. The modules can be stored inmemories 820, 920 and executed by processors 810, 910. The memories 820,920 can be implemented within the processors 810, 910 or external to theprocessors 810, 910 in which case those can be communicatively coupledto the processors 810, 910 via various means as is known in the art.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope of the present disclosure.

1. A method for configuring a frame by a network node in a wirelesscommunication system, the method comprising: configuring a frame inwhich a first cyclic prefix (CP) is allocated to a first symbol in every0.5 ms and a second CP is allocated to remaining symbols in every 0.5ms; and communicating with a user equipment (UE) by using the frame,wherein a length of the first CP is longer than a length of the secondCP.
 2. The method of claim 1, wherein the length of the first CP and thelength of the second CP, in terms of sampling time, depends on asubcarrier spacing.
 3. The method of claim 1, wherein the frame is afirst time duration with a first subcarrier spacing, and wherein thefirst subcarrier spacing is a reference subcarrier spacing.
 4. Themethod of claim 3, wherein the first time duration consists of 7orthogonal frequency division multiplexing (OFDM) symbols based on thereference subcarrier spacing.
 5. The method of claim 3, furthercomprising configuring a second time duration with a second subcarrierspacing, wherein the second subcarrier spacing is power of 2 for thefirst subcarrier spacing.
 6. The method of claim 5, wherein the firsttime duration and the second time duration are aligned with each otherat OFDM symbol level.
 7. The method of claim 5, wherein the first timeduration and the second time duration are aligned with each other atslot level.
 8. The method of claim 5, wherein the first time durationand the second time duration are aligned with each other at subframelevel.
 9. A network node in a wireless communication system, the networknode comprising: a memory; a transceiver; and a processor, coupled tothe memory and the transceiver, that: configures a frame in which afirst cyclic prefix (CP) is allocated to a first symbol in every 0.5 msand a second CP is allocated to remaining symbols in every 0.5 ms, andcontrols the transceiver to communicate with a user equipment (UE) byusing the frame, wherein a length of the first CP is longer than alength of the second CP.
 10. The network node of claim 9, wherein thelength of the first CP and the length of the second CP, in terms ofsampling time, depends on a subcarrier spacing.
 11. The network node ofclaim 9, wherein the frame is a first time duration with a firstsubcarrier spacing, and wherein the first subcarrier spacing is areference subcarrier spacing.
 12. The network node of claim 11, whereinthe first time duration consists of 7 orthogonal frequency divisionmultiplexing (OFDM) symbols based on the reference subcarrier spacing.13. The network node of claim 11, further comprising configuring asecond time duration with a second subcarrier spacing, wherein thesecond subcarrier spacing is power of 2 for the first subcarrierspacing.
 14. The network node of claim 13, wherein the first timeduration and the second time duration are aligned with each other atOFDM symbol level or slot level or subframe level.